Inclinometer



Aug. 29, 1933. P. WEBER 1,924,339l

INCLINOMETER Filed Nov. 3, l1930 2 sheets-sheet 1 INVENTOR Plzz'lb WeberB52/5M ATT'ORNEY P. wEB'ER INCLINOMETER Aug. 29, 1933.

Filed NOV. 3, 1930 2 Sheets-Sheet 2 t INVENTOR Plzili lfeber.

BY 576M- ATTORNEY Patented Aug. 2.9, 1933 UNITED STATES PATENT OFFICElNcLlNoMETEn Application 'November 3, 1930. serai' No. 493,114

c claims. (ci. 33zzo) I The present invention relates to means forindicating longitudinal inclinations of a mobile object, andmoreparticularly to devices` employing gravitational effects forproducing the indications.

I In indicating devices of the above type, gyroscopic means aregenerally employed for overcoming the -effect of acceleration forces onthe gravitationalelement by utilizing the precessional forces of agyroscope to balance or counteract the .10 effect of said accelerationforces. It has been due to an inclination upward from lev'el flight at..

the same cruising speeds and therefore a greater balancing forceisrequired for thesame angle of inclination in descent than in ascent. A

It is one of thev objects of 'the present invention to provide a novelindicating devicey of the above4 type wherein accurate indications areproduced regardless of whether an aircraft, for example, on

which the device is mounted is moving upwardor downward.V

VAnother object is to provide an inclinometer wherein the sameindication is produced for .an

angle of inclination downwardas for the same angle of inclination upwardwhen the plane inclines downward or upward from level flight while yingat its normal cruising speed.

Another object is to provide in an inclinometer of the type employinggyroscopic means for balancing thel effects of acceleration, novel means4whereby a balancing "force is produced in greater 'proportion for anangle of inclination downward and in lesser proportion for the sameangle of inclination upward, so that equal indications are produced forthe same angle of inclination in descent as in ascent of the aircraft onwhich the inclinometer is employed. 4

A further object is to provide in an inclinometer v of the above type,novel means wherebytheg'ravi` 45 tational Aelement is moved in adirection opposite gravitational element dueto gravity, acceleration,

and gyroscopic procession and the resultant motion produced in descentis equal to the resultant produced in ascent for the same angle ofinciination.

The above and other objects and advantages of 00 the invention willappear more fully hereinafter from a consideration of the detaileddescription which follows, together with the accompanying drawings,wherein is illustrated one embodiment y of the invention. It is to beexpressly understood, 'p5 however, that the drawings are for the purposeof illustration and description only, and are not designed as adefinition of the limits of the invention, reference being had for thispurpose to the appended claims.

In-the drawings, wherein like reference characters refer to like partsthroughoutl the several views,

Fig.. 1 'is a partial longitudinal section of one form of the deviceembodying the present invention;

- Fig. 2 is a right end view of Fig. 1, with the cover-glass, indicator,and dial removed;

Fig. 3 isa u: :n u tic view illustrating the principle of operation ofthe apparatus embodying the'invention; and 1 Fig. 4 is a front elevationof one form of motion-transmitting mechanism employed.

Referring tothe drawings, and more particularly to Figs. 1 and v2, thedevice embodyins the invention is of the type wherein a gravitationalelement, such as a simple pendulum for example.. is suspended andarranged to swing on a transverse axis of the mobile object whoselongitudinal inclination is to be indicated.

In the form shown, the device comprises a suitable casing 5 providedlwith a peripheral flange 6 at the front end thereof having projectionsor ears 'I whereby the device may be mounted on an instrument panel byany suitable means, such as bolts or screws (not shown). A supportingmembersinthe'formofaring havinganintegral cross-bar 9 isprovided at thefront end of the casing and adapted to abut a circumferential wall 10provided on theinterior of the casing.l A plate 11 is secured to saidsupporting member by suitable means, such as screws 12, which arecountersunk so that a dial 13 may-be secured thereto, as by means ofscrews- 14. A cover 15of some suitable transparent material, such asglass or celluloid, is .provided for closing the casing and throughwhich the dial'is adapted to be viewed, s aid cover-glass being held inposition by means of a clamping ring 1s. :A avitationai element in mthefform of a simple penduluxnll is suspended within the casing at 18aas by means of a bracket 18, the axis of suspension being transverse ofthe aircraft on which the device is mounted, thereby permitting alongitudinal swing of the pendulum 17 when the aircraft-is inclineddownward as in descent or inclined upward as when climbing.

Means are provided for. transmitting the swing of the pendulum 17 to apointer 19, the latter being positioned in front of the dial 13 fortraversing a suitable scale (not shown) marked on said dial, and in theform shown said means comprise a rod 20, one end of which is secured tothe other end pivotally connected to a link member 26 as indicated at27. The link member 26 is` secured to or made integral with a rockingshaft 28 extending 4transversely of the casing and suitably journaledvat its ends in projecting members 29 secured toor made integral with aplate 30.

Pins 31 and 32 are provided at one end of the rocking shaft 23 betweenwhich is adapted to extend one end of a rod. 33, the latter passingthrough a pivot member 34 made integral with or secured to a gear sector35 provided with gear teeth 36. The other end of the rod 33 is providedwith a counterweight 37. Gear sector 35 is journaled in the plate l1 bymeans of a pin 38 and is also provided at the lower end with acounterweight 39 for urging the sector to normal position. The gearteeth 36 are arranged to mesh with a pinion 40 which is integral with ashaft 41 journaled in the plates 30 and 11, one end ci the shaftextending through the plate 11 and through the dial 13 and to which issecured the pointer 19.

The dash-pot 22 is connected with the atmosphere outside the casing bymeans of a valve 42 arranged to be adjusted by means of a screw 32, andby means of the loose pivotal connections between the piston and thependulum serves to prevent any vibrations of the latter from beingtransmitted to the pointer. The pointer is not actuated until a positivemotion is transmitted to the piston by the pendulum.

lt will be apparent from this construction that when the pendulum 17swings to the left or to the right as viewed in Fig. 1 due to aninclination of the casing downward or upward, respectively, pistonmember 21 will be Amoved either to the left or to the right, causing rod24, by means of its connection,25, to actuate the lever 26 through thepivot connection 27. Actuation of the lever 26 will cause rotation ofthe shaft 28 in its journal members 29 `and produce an arcuate 'movementof the pins 31 and 32 upward yor downward. Movement of the pins 31 and32y will in turn swing the rod 33 in its'pivot 34, thereby causing anangular movement of the gear sector 35, thus rotating the pinion 40 andmoving the pointer i9 across the dial 13.

hereinbefore stated, gyroscopic means are provided for counteracting theeffect of accelera- 'tion forces onthe pendulum i7, and in the formshown comprise a rotor 44 mounted in the frame 45 as by means of pivotpins 46 and 47, on which it is adapted to rotate. The rotor is providedwith a series of peripheral buckets 48 which cause it to rotate when astream of air is directed there-- on as by means of a noz'zle 49. lt isobvious that a suitable electric drive may be provided instead l or" thepneumatic drive ii desired.

Frame45 is pivotally mounted, as by means of pivot pins 50 and 51 forrotation about the longitudinal axis of the casing 5, and hence of theycraft on which the instrument is mounted, due

to precessional forces of the rotor 44 acting.

thereon when the latter is turned about an axis y perpendicular to itsaxis of rotation and perpendicular to the axis passing through the pivotpins 50 and 51.

It isl well known in the art that a gyroscope rotated at high speed andthen turned bodily will precess and tend to establish its axis ofrotation parallel to the axis of turning. Hence, in Fig. 1, if thecasing' be inclined upward or downward, the rotor 44 will be turnedclockwise or counterclockwise about an axis perpendicular to the axis ofrotation i and the longitudinal 'axis passing through pins 50 and 51,and due to this rotation, preces'sion will take place, tending toestablish the axis of.. rotation parallel to the axis of turning,thereby causing rotation of the frame 45 about the longitudinal axispassing through pins 50 and 5l.

Means are provided for transmitting this precessional motion of theframe 45 to the pendulum 17, and in the form shown comprise a plate 52secured to the gyroscope frame 45 in any suitable manner, as by means ofscrews 53 and arranged to rotate with said frame about the longitudinalaxis of the latter. The plate is provided with a projecting portion 54to one end of which is .rotation of the frame 45 on its pivot pins 50and 51 due to precession of the rotor will be transmitted through theplate 52 and the connecting l y cession of the rotor 44 will be in sucha direction as to cause movement of the pendulum 17 in the samedirection as the swing thereof due to gravity. in this instance to theleft, since4 the acceleration forces due to the speeding-up of the craftin descent are to the right--in` other words, precessional movement isin the direction opposite to the movement produced by the force ofacceleration-thereby balancing or neutralizing the latter so that thependulum 17 will vassume a substantially vertical position such as'itwould assume if only gravity were acting thereon and no accelerationforces were present, thereby giving a true indication of the angle ofinclination on the dial 13 by means of the pointer 19.

When anv aircraft is flying level at anormal cruising speed and tends toincline downwardv or upward from such level flight due to disturbinginfluences, the rate of change of speed of the craft in moving downwardis greater than said ,rate when moving upward or climbing withoutclination from level flight at normal cruising speeds than when thecraft is ascending or climbing at the same angle due toan upwardinclination from such level flight. To this end, the pivot connection 56of the rod 55 (referring to Fig. 4) is selected at such a point on therotary plate 52 that for the same angle of precession (as indicated bya) in a counter-clockwise direction, point 56 will move a greatervertical .distance h than in a'counter-clockwise direction as indicatedby` h', it being understood that plate 52 moves counter-clockwise fordescent, thereby imparting greater motion to the pendulum, and

clockwise in ascent, therebyv imparting a`lesser vious, though, thatwhen an aircraft is descend` llum to the position 17h.

ing it begins to accelerate due to'gravity acting' thereon in additionto its own power of propulsion. and therefore 'the pendulum tends tomove only to the position indicated in dotted lines at 1 '1b, but oninclination of the aircraft, which constitutes a turning about thetransverse axis thereof, the gyroscope precesses through an angle equalto the angle of inclination and therefore imparts a motion to thependulum through the plate 52 and its cooperating linkage, to overcomesaid tendency, whereby the pendulum may move to the proper positionindicated atl'Ia. On the other hand, when the aircraft is inclinedupward, as in climbing, the pendulum 17 takes the position. as indicatedin dotted line at 17a' for the same angle of inclination but, due to aload on the enginein propelling the craft against the force of gravitywithout materially increasing the engine speed, deceleration takesplace, and the force of the deceleration tends to move the pendu- Thegyroscope now precesses in the opposite direction, thereby causing thependulum to assume the .position 17a', which is the true position' forthe angular inclination. It will be noted, however, that the angulardistance betweenUv 17a and 17h is greater than between 17a land 17h',the difference between the two being compensated for by the selectedlocation of the pivot Apoint 56 shown in Fig. 4, as explainedhereinbefore. It will thus be' seen that the forces of acceleration anddeceleration acting upon the pendulum are compensated for orneutralized, thereby causing thelatter to assume the proper position forany angleof inclination and thus -prodi'fcing a corresponding in.-dication on the dial by means of the pointer,

65 which is actuated by the pendulum.

There is thus provided an inclinometer which is comparatively simple inconstruction, efficient .and reliable in operation, and one whichproduces accurate indications of inclination of the mobile object onwhich the, device is mounted regardless of whether the object isinclined downward or upward. There is also provided `amotion-transmitting mechanism embodying novel arrangement of theelements, Awhereby the'effect of the force of acceleration isautomatically compensated for, thus producing a true jand accurateindication on the device in which the mechanism is embodied.

. While only one embodiment of the invention has been illustrated anddescribed, various other changes and modifications, which will nowappear to those skilled in the art, may be made without departing fromthe scope of the invention. For example, the motion-transmittingmechanism may be embodied in various mechanical forms other than thatshown in the drawings, and reference is therefore to be had to theappended claims forv a definition of the limits of the invention.

What is claimed is:

1. In combination, a case, a pendulum pivotally mounted in said case,means operatively connected to said pendulum for indicating the angulardisplacement of said pendulum relative to said case, a frame, agyroscope rotatably supported in said frame so thatthe latter canprecess about an axis perpendicularto the axis of swing of the fpendulum, and means connecting said 4pendulum and frame for causingsaidpendulum and frame to move simultaneously in relation to said case butin predetermined relation to each other, said last mentioned meansincluding a connection for affecting the. pendulum to a greater extentby the precessional 'movement of the gyroscope in one direction and to alesser extent by the precessional movement of said gyroscope through thesame angular distance in an opposite direction.

2. In an inclinometer for aircraft, the combination of a pendulousdevice arranged to be acted upon by acceleration forces as well as bythe force of gravity when an aircraft on which the inclinometer ismounted is descending or ascending, gyroscopic means mounted to precessabout 'an axis perpendicular to the axis of swing of the pendulousdevice for neutralizing or balancing said acceleration forces, meansfor` transmitting the precessional forces of the gyroscope to thependulous device including a pivotal connection between the gyroscopeand the pendulous device arranged on a radial line extending normallyfrom the axis of precession of the gyroscope at an angle lss than ninetydegrees from ahorizontal plane passing through and including said axisof precession so that the angular displacement of the/pendulous devicewith respect to the aircraft will be the same in descent as inascentwithl the sameangle of'inclination of the air-- craft, and meansoperatively connected Awith said pendulus device for indicating saidangular displacements.

3. In an inclinometer for aircraft, the combination of a pendulousdevice arranged to be acted upon by acceleration forces as well as bythe force of gravity when an aircraft on' which the incli nometer .ismountedv is descending or ascending gyroscopic meansarranged to precessabout anaxis for neutralizing or balancing said accelerartion forces,`means fortransmitting the precessional forces of the gyroscope to thependulous device including a pivotal connection between the gyroscopeand the pendulous device arranged on a Vradial line extending normallyfronr theA axis of precession of the gyroscope at ,an angle less thanninety degrees above a horizontal' plane passing through and including'said axisof precession so that the angular displacement of the pendulousdevice r with respect to the aircraft will be the same in descent as inascent for the same angle of inclination of theairraft, and meansoperatively-connected with'said pendulous device for indicating'saidangular displacements..

4. In an inclinometer for aircraft, the combination of a pendulousdevice arranged to be acted upon by acceleration forces as well as bythe force of gravity when an aircraft on Whichthe inclinorneter ismounted is descending or ascending, gyroscopic means arranged to precessabout an axis for neutralizing or balancing said acceleration forces,means for transmitting precessional forceswf the gyroscope to thependulous device including a link having one end thereof pivotallyconnected to the gyroscope on -a radial line extending normally from theaxis of precession of the gyroscope at an angle less than ninety degreesabove a horizontal plane passing through and including said axis ofprecession'and the other end pivotally connected to the pendulous devicebelow said horizontal plane so that the pendulous device will beeffected to a greater I said aircraft, and means operatively connected,

with said pendulous device for indicating said angular displacements.

5. In an inclinometer for aircraft, the combination of a pendulousdevice arranged to be acted upon by acceleration forces as Well asbytheforce of gravity when an aircraft on which the inclinometerismOunted is descending or ascending, gyroscopic means for neutralizingor balancing said acceleration forces including a rotor arranged forrotation about an axis, a frame supporting said rotor and arranged forangular movement about an axis perpendicular to the axis of rotation .ofsaid rotor so that it may be angularly displaced by the precession ofthe rotor r produced on turning of the Iaircraft on which theinclinometer is mountedl about a transverse axis, means for transmittingthe precessional movementsof the gyroscope to the pendulous' deviceincluding a plate secured'to said gyroscope frame, and a links havingone endthereof pivotally connected to said plate on a radial lineextending normally from the axis of precession of d tent by theprecession of said gyroscope in one l direction and to a lesser extentby the precession of said gyroscope through the same angular distance in`an opposite direction, thereby producing equal angular displacements ofsaid pendulous device withrespect to the aircraft in descent andascentfor the same angle of inclination of said aircraft, and meansoperatively connected to said pendulous device for indicating saidangular displacements.

6.l In combination, a pendulum, means mounting said pendulum to swingabout an axisfa gy-y :lao

iso

